Square Force-Sensitive Resistor - Original
What Is It?
A Force-Sensitive Resistor (FSR) that detects pressure/force applied on its surface.
Original typically refers to high-quality, calibrated versions (e.g., Interlink-type FSRs).
The square sensing area allows uniform force detection over a flat surface.
Key Features
Analog Force Detection: Output varies with applied pressure
Thin & Flexible: Can be integrated into surfaces
Fast Response Time (<10 ms)
Lightweight & Durable
Wide Dynamic Range (light touch to heavy pressure)
Simple Interface (voltage divider circuit)
Technical Specifications (Typical)
Value Operating Voltage 3.3 V 5 V (via voltage divider) Output Type Analog (variable resistance) Force Range ~0.1 N to 100 N (approx.) Response Time <10 ms Thickness ~0.45 mm Resistance (No Force) >1 M Resistance (With Force) ~1 k 10 k Repeatability Good (better in original versions)
How It Works
The sensor has conductive layers separated by a pressure-sensitive material.
When force is applied, layers come closer resistance decreases.
This resistance change issistor divider.
Microcontroller reads voltage via ADC (analog input).
Basic Connection
One terminal VCC (through fixed resistor)
Other terminal Analog pin + GND
Common setup:
Use a 10 k resistor to form a voltage divider.
Working Behavior
No Force Very High Resistance Low Voltage Output
More Force Lower Resistance Higher Voltage Output
Output is non-linear requires calibration for accurate force values.
Applications
Pressure sensing pads
Touch-sensitive interfaces
Robotics (grip forcng)
Medical/rehabilitation devices
Interactive systems & gaming
Important Notes
Not a Load Cell: Not suitable for precise weight measurement.
Non-linear Output: Requires calibration for better accuracy.
Force Distribution Matters: Works best with evenly applied force.
Wear Over Time: Repeated heavy pressure can degrade performance.
Summary
Type: Force-Sensitive Resistor (FSR)
Shape: Square sensing area
Output: Analog (resistance-based)
Best Use: Detecting presence and relative